Experimental Characteristics Of Fe-Ni/Mg Catalytic Pyrolysis Of Pine Needles To Hydrogen-rich Syngas In A Fixed-bed Reactor

With the uncontrolled use and large-scale development of fossil fuels,energy exhaustion and increasingly serious environmental pollution have gradually revealed great harm to human society and fragile ecosystem.Biomass has been favored by experts and scholars at home and abroad due to its characteristics of cheap and easy access,abundant reserves,clean and environmental protection,wide distribution,renewable and carbon neutral.In this study,pine needles were used as raw materials to carry out catalytic pyrolysis experiments on pine needles by supporting Fe,Ni,Fe-Ni,Fe-Ni/Mg catalysts.The main contents and results are as follows:(1)The increase of pyrolysis temperature is conducive to the increase of biomass syngas yield.At 750°C,the gas yield reaches 24.44 wt.%,and the yield of H₂ and CO reaches 46.48 m L/g and 63.25 m L/g,respectively.(2)Fe,Ni and Fe-Ni catalysts can all increase the yield of biomass syngas and the yield of H₂ and CO.When Fe loading is 12 wt.%,the yield of biomass syngas is 30.18wt.%,and the yield of H₂ and CO reaches 88.56 m L/g and 67.67 m L/g,respectively.When the Ni load was 8 wt.%,the maximum H₂ yield reached 101.21 m L/g.When the molar mass of Fe and Ni was 1:2,the gas yield and H₂ yield reached the maximum,which were 29.68wt%and 100.84 m L/g,respectively.(3)Mg helps to improve the catalytic effect of 3Fe1Ni(the molar mass ratio of Fe and Ni is 3:1,and the total loading amount of Fe and Ni is 8%of the biomass mass)catalyst.When the Mg loading is 0.2 wt.%,the gas yield is 34.38 wt.%,and the H₂ and CO yields are 123.94 m L/g and 86.83 m L/g,respectively.When the Mg load was 5wt%,the gas yield was 34.43 wt.%,and the H₂ and CO yields were 132.37 m L/g and 86.84m L/g,respectively.(4)The increase of heating rate can increase the gas yield and H₂,CO,and reduce the yield of water and biomass coke.In CFP750(the heating rate is about 100°C/min,pyrolysis temperature of 750°C),gas yield reached 35.54 wt.%,H₂ yield and CO yield were 155.41 m L/g and 107.65 m L/g,respectively,water yield and biomass coke yield were 21.78 wt.%and 25.70 wt.%,respectively.In CSP750(heating rate of 10°C/min,pyrolysis temperature of 750°C),gas yield reached 34.27 wt.%,H₂ yield and CO yield were 120.98 m L/g and 86.86 m L/g,respectively.Water and biomass coke yield were28.41 wt.%and 26.53 wt.%,respectively.(5)Combined with the analysis of the characterization results of XRD,H₂-TPR,NH₃-TPD,CO₂-TPD,FT-IR and the experimental results,the possible mechanism of catalytic pyrolysis of cellulose,hemicellulose and lignin,the possible mechanism of catalytic reforming of small molecules(H₂O,CH₄)and the possible mechanism of lattice O transfer of Fe₂O₃ and Ni O are proposed.